W Jasper mark

Steve Rogers from New Jersey is anxious to track down a maker's mark.

The photograph shows a maker’s stamp in the blade of a spontoon spearhead dating roughly 1750-1780 by form. Steve believes the maker to be William Jasper, who emigrated to America in 1763 and worked in New York and Boston until his death in 1786. He would like to confirm the identity and that it was likely made in America rather than Britain before he emigrated. Jasper advertised as a cutler, making all sorts of edge tools, including saws, knives and surgical instruments, and claimed some experience in drawing teeth. He gave his background as simply “England” in one case and London in particular in another.

This is one of two stamps on the piece. There is no ambiguity about the reading as, "W. Jasper.” (The other stamping shows the end of his name more clearly) Any assistance would be greatly appreciated.